iodine/iodine.c

302 lines
5.6 KiB
C
Raw Normal View History

2006-06-05 12:41:08 +00:00
/*
2006-06-05 14:15:53 +00:00
* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@kryo.se>
2006-06-05 12:41:08 +00:00
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
2006-06-05 14:43:04 +00:00
#include <string.h>
2006-06-05 14:46:10 +00:00
#include <signal.h>
2006-06-05 15:13:30 +00:00
#include <unistd.h>
2006-08-13 18:58:54 +00:00
#include <netinet/in.h>
2006-06-05 15:13:30 +00:00
#include <sys/types.h>
2006-06-11 19:54:38 +00:00
#include <sys/socket.h>
2006-06-05 23:34:23 +00:00
#include <sys/stat.h>
#include <fcntl.h>
2006-06-05 14:43:04 +00:00
#include <err.h>
#include <pwd.h>
2006-06-06 00:17:28 +00:00
#include <arpa/inet.h>
2006-06-06 17:59:24 +00:00
#include <zlib.h>
2006-06-05 12:41:08 +00:00
#include "tun.h"
#include "structs.h"
2006-06-05 13:38:10 +00:00
#include "dns.h"
2006-06-05 12:41:08 +00:00
2006-06-06 00:18:29 +00:00
#ifndef MAX
#define MAX(a,b) ((a)>(b)?(a):(b))
#endif
2006-06-11 18:07:26 +00:00
2006-06-05 14:46:10 +00:00
int running = 1;
2006-06-11 18:07:26 +00:00
int tun_fd;
int dns_fd;
2006-06-05 14:46:10 +00:00
static void
2006-06-11 18:07:26 +00:00
sighandler(int sig) {
2006-06-05 14:46:10 +00:00
running = 0;
}
2006-06-05 14:43:04 +00:00
static int
tunnel(int tun_fd, int dns_fd)
{
int i;
2006-06-05 15:31:07 +00:00
int read;
2006-06-05 14:43:04 +00:00
fd_set fds;
2006-06-05 15:31:07 +00:00
struct timeval tv;
char in[64*1024];
long outlen;
char out[64*1024];
2006-06-05 23:34:23 +00:00
2006-06-05 14:46:10 +00:00
while (running) {
tv.tv_sec = 1;
tv.tv_usec = 0;
2006-06-05 14:43:04 +00:00
FD_ZERO(&fds);
2006-06-06 02:39:37 +00:00
if (!dns_sending())
2006-06-05 20:05:11 +00:00
FD_SET(tun_fd, &fds);
2006-06-05 14:43:04 +00:00
FD_SET(dns_fd, &fds);
i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv);
if(i < 0) {
if (running) {
warn("select");
}
2006-06-05 14:43:04 +00:00
return 1;
}
if(i == 0) {
2006-06-05 23:49:18 +00:00
dns_ping(dns_fd);
2006-06-05 14:43:04 +00:00
} else {
if(FD_ISSET(tun_fd, &fds)) {
read = read_tun(tun_fd, in, sizeof(in));
if(read <= 0)
continue;
outlen = sizeof(out);
compress2(out, &outlen, in, read, 9);
dns_handle_tun(dns_fd, out, outlen);
2006-06-05 14:43:04 +00:00
}
if(FD_ISSET(dns_fd, &fds)) {
read = dns_read(dns_fd, in, sizeof(in));
if (read <= 0)
continue;
outlen = sizeof(out);
uncompress(out, &outlen, in, read);
write_tun(tun_fd, out, outlen);
if (!dns_sending())
dns_ping(dns_fd);
2006-06-05 14:43:04 +00:00
}
}
}
return 0;
}
2006-06-11 16:13:40 +00:00
static int
handshake(int dns_fd)
{
int i;
int r;
char *p;
2006-06-11 18:07:26 +00:00
int mtu;
2006-06-11 16:13:40 +00:00
int read;
fd_set fds;
int timeout;
char in[4096];
struct timeval tv;
timeout = 1;
2006-06-11 19:54:38 +00:00
for (i=0; running && i<5 ;i++) {
2006-06-11 16:13:40 +00:00
tv.tv_sec = timeout++;
tv.tv_usec = 0;
dns_handshake(dns_fd);
FD_ZERO(&fds);
FD_SET(dns_fd, &fds);
r = select(dns_fd + 1, &fds, NULL, NULL, &tv);
if(r > 0) {
read = dns_read(dns_fd, in, sizeof(in));
2006-06-11 18:07:26 +00:00
if(read < 0) {
2006-06-11 16:13:40 +00:00
perror("read");
continue;
}
2006-06-11 19:54:38 +00:00
if (read > 0) {
p = strchr(in, '-');
if (p) {
*p++ = '\0';
mtu = atoi(p);
if (tun_setip(in) == 0 && tun_setmtu(atoi(p)) == 0)
return 0;
else
warn("Received handshake but b0rk");
}
2006-06-11 18:07:26 +00:00
}
2006-06-11 16:13:40 +00:00
}
printf("Retrying...\n");
}
return 1;
}
2006-06-11 12:18:49 +00:00
extern char *__progname;
static void
usage() {
2006-08-14 16:36:32 +00:00
printf("Usage: %s [-v] [-h] [-f] [-u user] [-t chrootdir] [-d device] "
2006-06-11 14:29:36 +00:00
"nameserver topdomain\n", __progname);
exit(2);
}
2006-06-11 13:14:57 +00:00
static void
help() {
2006-06-11 13:27:48 +00:00
printf("iodine IP over DNS tunneling client\n");
2006-06-24 10:31:16 +00:00
printf("Usage: %s [-v] [-h] [-f] [-u user] [-t chrootdir] [-d device] "
2006-06-11 14:29:36 +00:00
"nameserver topdomain\n", __progname);
2006-06-11 22:02:26 +00:00
printf(" -v to print version info and exit\n");
printf(" -h to print this help and exit\n");
printf(" -f to keep running in foreground\n");
2006-06-11 13:14:57 +00:00
printf(" -u name to drop privileges and run as user 'name'\n");
2006-06-11 14:34:27 +00:00
printf(" -t dir to chroot to directory dir\n");
2006-06-24 10:28:24 +00:00
printf(" -d device to set tunnel device name\n");
2006-06-11 17:47:39 +00:00
printf("nameserver is the IP number of the relaying nameserver\n");
printf("topdomain is the FQDN that is delegated to the tunnel endpoint.\n");
2006-06-11 13:14:57 +00:00
exit(0);
}
2006-06-11 13:27:48 +00:00
static void
version() {
2006-06-11 13:37:44 +00:00
char *svnver = "$Rev$ from $Date$";
2006-06-11 13:27:48 +00:00
printf("iodine IP over DNS tunneling client\n");
printf("SVN version: %s\n", svnver);
exit(0);
}
2006-06-05 12:41:08 +00:00
int
main(int argc, char **argv)
2006-06-05 12:41:08 +00:00
{
2006-06-11 14:29:36 +00:00
int choice;
char *newroot;
char *username;
2006-06-24 10:28:24 +00:00
char *device;
2006-06-11 13:05:41 +00:00
int foreground;
2006-06-11 14:29:36 +00:00
struct passwd *pw;
newroot = NULL;
username = NULL;
2006-06-24 10:28:24 +00:00
device = NULL;
2006-06-11 13:05:41 +00:00
foreground = 0;
2006-06-11 12:45:46 +00:00
2006-06-24 10:28:24 +00:00
while ((choice = getopt(argc, argv, "vfhu:t:d:")) != -1) {
switch(choice) {
2006-06-11 13:27:48 +00:00
case 'v':
version();
break;
2006-06-11 13:05:41 +00:00
case 'f':
foreground = 1;
break;
2006-06-11 13:14:57 +00:00
case 'h':
help();
break;
case 'u':
username = optarg;
break;
2006-06-11 14:29:36 +00:00
case 't':
newroot = optarg;
break;
2006-06-24 10:28:24 +00:00
case 'd':
device = optarg;
break;
default:
usage();
2006-06-11 14:33:59 +00:00
break;
}
}
if (geteuid() != 0) {
printf("Run as root and you'll be happy.\n");
usage();
}
argc -= optind;
argv += optind;
2006-06-11 12:18:49 +00:00
2006-06-11 14:29:36 +00:00
if (argc != 2)
usage();
2006-06-11 12:18:49 +00:00
if(username) {
pw = getpwnam(username);
if (!pw) {
printf("User %s does not exist!\n", username);
usage();
}
}
2006-06-24 10:28:24 +00:00
if ((tun_fd = open_tun(device)) == -1)
goto cleanup1;
if ((dns_fd = open_dns(argv[1], 0, INADDR_ANY)) == -1)
2006-06-11 14:42:19 +00:00
goto cleanup2;
2006-06-11 20:02:26 +00:00
if (dns_settarget(argv[0]) == -1)
2006-06-11 19:54:23 +00:00
goto cleanup2;
printf("Sending queries for %s to %s\n", argv[1], argv[0]);
2006-06-05 14:46:10 +00:00
2006-06-11 18:07:26 +00:00
signal(SIGINT, sighandler);
signal(SIGTERM, sighandler);
2006-06-11 14:29:36 +00:00
2006-06-11 16:13:40 +00:00
if(handshake(dns_fd))
goto cleanup2;
2006-06-11 14:29:36 +00:00
if (newroot) {
if (chroot(newroot) != 0 || chdir("/") != 0)
err(1, "%s", newroot);
seteuid(geteuid());
setuid(getuid());
}
2006-06-05 14:46:10 +00:00
2006-06-11 13:05:41 +00:00
if (!foreground) {
printf("Detaching from terminal...\n");
2006-06-11 13:05:41 +00:00
daemon(0, 0);
umask(0);
alarm(0);
}
if (username) {
if (setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) {
printf("Could not switch to user %s!\n", username);
usage();
}
}
2006-06-05 14:43:04 +00:00
tunnel(tun_fd, dns_fd);
2006-06-05 12:41:08 +00:00
2006-06-11 14:42:19 +00:00
cleanup2:
2006-06-05 14:43:04 +00:00
close_dns(dns_fd);
close_tun(tun_fd);
cleanup1:
2006-06-05 12:41:08 +00:00
return 0;
}